The present invention relates to multiple sprocket assemblies for bicycles and more particularly, to a multiple sprocket assembly including sprockets having teeth with shifting aids that facilitate both shifting of the chain and maintaining chain engagement on the sprockets.
To enable controlled shifting from a larger sprocket to a smaller sprocket, a bicycle chain should be guided onto the destination sprocket. This is achieved by the chain rollers dropping into the tooth roots of the smaller sprocket, preventing the chain from riding on top of the teeth. An almost jerk-free shifting operation results, even under load. Several problems may occur while shifting to a smaller sprocket. The chain may not readily drop into its seated position on the destination sprocket. Even if the chain does drop into a seated position with the rollers seated in the tooth roots, there is no guarantee that the chain will remain engaged with the teeth due to excessive lateral play. Further, shifting errors may cause a chain to break under load, exposing the cyclist to an abrupt jerking motion causing muscles cramps.